Improvement of automotive tools and components through the applications of deep cryogenic treatments (CRYO) : final report

The main aim is to develop and apply deep cryogenic treatments (DCT) in order to improve wear resistance and fatigue life of: - automotive products (gears, transmission parts, bearings, engine components, etc.). This may lead to weight reduction, - metal cutting tooling (punches, dies, moulds, etc.) and machining tools (hoobs, broaches, cutters, slitting knives, etc.). This may lead to an increase in the tools' life. It will pay special attention to the microstructural changes and the fatigue behaviour improvement that takes place as a function of the cryogenic treatment route. For this purpose a set of steel grades and products has been selected and used to demonstrate the benefits of DCT. The automotive products have an improved fatigue life. The metal cutting tooling does not have any benefit on the wear resistance. The main reason is that it has been demonstrated that the DCT can introduce compression residual stresses. This has a positive impact at the high cycle fatigue life range, and only the automotive components under the study work at these conditions. Metal cutting tooling works under low cycle fatigue conditions, so the relative influence of a residual compressive stress is lower.